Citrus pigment waste could offer cheap sweeteners for industry

Researchers in Italy have developed a process to produce high
purity sugars from citrus processing waste that could offer natural
and inexpensive sweeteners for the food and beverage industries.

The process, which combines passing the waste through a resin and
then ultra-filtration, produces "a brilliant and almost
colourless final sample that can be used as a natural sweetener for
food, drinks and, in European Union, for fruit nectars,"​ wrote
lead author Monica Scordino in the journal LWT - Food Science
and Technology​.
The new research, led by Emanuele Maccarone from the Università
degli Studi di Catania, obtained pigmented orange pulp waste from a
local processor used a neutral polystyrene-divinylbenzene (PS-DVB)
resin to recover flavanones and anthocyanin pigments.
The ultrafiltration (UF) process which followed this stage removed
enzymes and micro-organisms, and stabilised the product, said the
researchers. The final product was found to contain about 250 g/l
of sugars (33 per cent glucose, 30 per cent fructose and 37 per
cent sucrose), 9 g/l of citric acid and 1 g/l of pectins.
"The concentrate, obtained from a residue that otherwise must
be disposed, was a transparent liquid of slight amber colour with a
very low microbial count and could easily find application as a
natural sweetener in food and beverage industries,"​ wrote
Scordino and co-workers.
None of the researchers were available to comment prior to
publication, and it is not known if an industrial partner is
involved to further research and develop this sweetener
source.
The researchers stress that, although they focussed on an
analytical approach far away from an engineering purpose, the
results demonstrate the possibility to obtain high-quality sugar
syrup employable as food sweeteners.
"We believe that the economics of these treatments must be
evaluated adequately to make this process commercially profitable;
in facts even more costly methods, such us supercritical dioxide
extraction, may, with investigation, yield economically acceptable
applications in removal technology,"​ concluded the
researchers.
Waste disposal has increasingly found a place on government agendas
recently. The EU announced at the end of 2005 that reducing the
environmental impact of food waste, including cutting down on
landfills, would form part of a multi-million euro, five-pronged
research project aimed at the food and drink industry.
Source: LWT - Food Science and Technology​
Volume 40, Issue 4, Pages 713-721
"Highly purified sugar concentrate from a residue of citrus
pigments recovery process" ​Authors: M. Scordino, A. Di
Mauro, A. Passerini, E. Maccarone